The present invention relates to forage harvesters, and more particularly to a forage harvester incorporating means for preventing the production of long cobs.
Forage harvesters of the type herein concerned include a crop cutting cylinder having a plurality of circumferentially spaced cutting knives supported thereon and rotatable about a longitudinal axis, and an elongated stationary shear bar located adjacent the cutting knives of the cylinder in cutting cooperation therewith. One of the continuing problems with forage harvesters of this type has been the production of corn cobs chopped longer than the length of cut to which the machine is set. Cattle will reject these so-called "long cobs", especially if the grain has been removed. As a result, these long cobs lay in cattle feed bunks where they represent a waste of food energy and a nuisance to be cleaned up after each feeding.
Long cobs are typically produced when the bending couple imposed by a cylinder knife as it cuts laterally into a cob, cracks the cob one, two or three inches in front of the point of impact. This short section of cob is now no longer adequately supported by the machine or by the matrix of corn stalks in which it is embedded, and consequently it is frequently flipped into the cutting cylinder without further reduction in length.
One method successfully used to reduce the intensity of this problem is to grind the cutting edges of the cylinder knives to a bevel which so nearly matches the cutting arc of the knife that it imposes a resisting couple against the face of a cob being cut to balance the cutting forces thereby preventing the flipping action. This method, however, has not been totally satisfactory and there remains a need for an improved mechanism for preventing the production of long cobs.